Two-cycle engines are used to power watercraft, including smaller watercraft known as "personal" watercraft. These engines have the advantage that they are fairly powerful, and relatively lightweight and compact.
One particular disadvantage to the two-cycle engine is its emission content. Two-cycle engines exhaust large quantities of carbon monoxide (CO) and various hydrocarbons. When measures are taken to reduce the emission content of the two-cycle engine, other generally undesirable consequences result, such as an increase in the weight of the engine, a reduction of its power output or the like.
Four-cycle engines are commonly used as a power plant in other applications, such as automobiles. These engines have the advantage that their emission content is desirably lower and the engines have a high power output.
On the other hand, four-cycle engines are generally arranged with oil-filled crankcases or reservoirs positioned at the bottom of the cylinder block. In addition, the oil filter is positioned at the bottom of the engine. This impedes use of the four-cycle engine in this type of watercraft. In particular, when this type of engine is mounted in a watercraft in a manner in which the drive shaft is generally horizontally extending, the oil reservoir and oil filter are positioned under the engine adjacent the hull. This arrangement prevents the watercraft's owner from being able to service the engine, including replacing the oil and oil filter, through a service access which is normally provided in the top deck of the hull.
It is desired to provide a watercraft with a four-cycle engine having a lubricating system which is accessible for servicing and the like.